Field
This document relates to a touch and gesture sensing system and a driving method thereof.
Related Art
A user interface (UI) is configured so that people (users) are able to communicate with various electric and electronic devices and thus can easily control the devices as desired. Examples of the user interfaces include a keypad, a keyboard, a mouse, an on-screen display (OSD), and a remote controller having an infrared communication function or a radio frequency (RF) communication function. User interface technologies have continuously evolved to increase user's sensibility and handling convenience. The user interface as developed includes a touch UI, voice recognition UI, 3D UI, etc. A gesture UI for gesture sensing has been recently used in home appliances.
The touch UI senses an object that is directly touching the touch screen or approaching it from a level similar to that of the touch screen. The touch UI senses touch input from the user or object by using a touch screen including resistive or capacitive touch sensors.
The gesture UI spatially senses a user gesture or object motion by using a camera or a motion sensor. A capacitive touch sensing system is able to sense a finger directly touching it or in close proximity to a touch sensor, but it is difficult for the capacitive touch sensing system to sense spatial input (or gesture input) based on user motion or object motion at a place far from the touch sensor. The touch UI and the gesture UI are implemented in different systems. Implementing the touch UI and the gesture UI in different systems leads to steep cost rises and increases hardware complexity.
By embedding touch sensors in a display panel in an in-cell manner, a single frame period is divided into a display driving period and a touch sensor driving period to prevent a pixel driving signal from affecting a touch sensor signal. Embedding touch sensors in a display panel makes it difficult to secure a gesture sensing period without affecting the pixel driving signal and the touch sensor driving signal. Larger display panel screens make it more difficult to secure the gesture sensing period because the display driving period and the touch sensor driving period within 1 frame period becomes longer.